Restoring high-resolution text images to improve legibility and OCR accuracy

Hirobumi Nishida

doi:10.1117/12.583013

17 January 2005 Restoring high-resolution text images to improve legibility and OCR accuracy

Hirobumi Nishida

Proceedings Volume 5676, Document Recognition and Retrieval XII; (2005) https://doi.org/10.1117/12.583013
Event: Electronic Imaging 2005, 2005, San Jose, California, United States

Abstract

A new method for restoring high-resolution binary images is presented to improve legibility and OCR accuracy for low-resolution text images. The initially restored image is generated by simple techniques, and is then improved by integrating a variety of features obtained through image analysis. Missing strokes of characters are complemented based on topographic features. Contours of characters are then modified in terms of gradient magnitudes and curvatures along the contours. Finally, contours are beautified so that they look good to the human eye. The proposed method can deal with characters having complex structures such as Kanji, and entails relatively simple computation. Through experiments, it has been validated that the proposed method improves both OCR accuracy and legibility. In particular, smoothness and linearity along contours are significantly improved and strokes are restored correctly.

Citation Download Citation

Hirobumi Nishida "Restoring high-resolution text images to improve legibility and OCR accuracy", Proc. SPIE 5676, Document Recognition and Retrieval XII, (17 January 2005); https://doi.org/10.1117/12.583013

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